Among the most overrated activities in our society is the commencement speech, the occasion for prominent people to give advice that is usually unwanted and generally unheeded to college graduates who are eager for the speech to end so they can celebrate with family and friends.

The closest parallel to giving a commencement address is singing the “Star-Spangled Banner” at a ball game. No one came to hear you; they can’t have the event without you; and no one will remember your performance unless you screw it up. But this does not mean that people with decades of experience should never pass on our wisdom to those starting out. So I will use this column to share what I have learned in my 40 years of elected office to future candidates and office help.

First are three practical points

• Never throw anything away within one mile of where you were given it. After a speech very nice people will show you their appreciation by giving you a mug, plaque, T-shirt or proclamation. After a while you will have more of these than you need, want or can conveniently store. Throwing them away is much less rude than refusing them — but not if the donors find the item in a garbage can in the hotel in which you spoke.

• Always hold on to your coat, briefcase and anything else you will need when it’s time to leave. Kind people will offer to take your coat etc. and you will not know where they put it/them.

When you have to leave, the coat putters-away may have left or be busy elsewhere, or have given your items to someone else who put them somewhere else. What results is people asking loudly, where is the congressman (or whatever’s) coat. This is especially upsetting when you are trying to sneak out early.

• Do not give in to people who press you to explain why politicians with whom you both violently disagree believe the views which you are opposed to.

They will ask why Sen. ‘X’ opposes measures to combat damaging climate change. You will say you do not share his opinion, and are not comfortable explaining a viewpoint you strongly reject.

They will plead with you to voice Sen. X’s opinion. If you then give in, your interlocutor will then angrily debate you as if you believed it. Let them ask Sen. X.

Next are two moral guides. They are based on my perception that moral perfection is no more achievable by elected officials than by people in any other occupation. That is, they represent the best you should expect from real human beings facing real choices.

• Obey all the laws you vote for. We have too many laws on too many subjects for anyone to obey all of them, and people will understand a lapse regarding a relatively minor law by a politician — unless it is one she has supported. Even elected officials should take some right to privacy, but that should never become a right to hypocrisy.

• As a rule, tell the truth and nothing but the truth. People who want the whole truth should ask pointed questions, preferably with subpoena power. Lying is wrong. But volunteering damaging information is a very rare human practice, and insisting that politicians disclose bad news without being directly interrogated sets an impossible standard.

Finally, two rules bridge the distinction between the practical and the moral.

• Try hard to avoid saying something no one will believe. This may sound obvious, but it is often breached by officials pressed to explain away difficult facts. The rule against lying is insufficient protection here. Advisers, aides and others will often urge principals to give explanations that might not be false, but are wholly implausible. Acknowledging some fault is often a prerequisite to an effective defense on the larger issue at stake.

• Finally, because written words can be embarrassing when delicate negotiations or strategies are the subject — even when they are not evidence of bad acts or motives — follow the advice I received in 1967 when I went to work in a Boston mayoral campaign: Never write when you can talk; never talk when you can nod; and never nod when you can wink. And this wisdom has grown enormously in value in the age of e-mail.

Barney Frank is a retired congressman and author of landmark legislation. He divides his time between Maine and Massachusetts.